wet blanket vs spoilsport

wet blanket and spoilsport both are nouns.

Word	Noun	Adjective	Verb	Adverb
wet blanket	Yes	No	No	No
spoilsport	Yes	No	No	No

As nouns, wet blanket and spoilsport are synonyms defined as:

Other synonyms of wet blanket include killjoy, party pooper.

wet blanket (noun)	spoilsport (noun)
someone who spoils the pleasure of others	someone who spoils the pleasure of others